To putt accurately, the putter head must be aligned correctly, with the putting stroke preferably following a straight line path on the backstroke, as well as on the forward stroke up to and through the point of contact with the ball. And, since speed and distance are important considerations, it is useful to be able to accurately correlate the speed and distance of the putted ball with the length of the backstroke.
Many existing putting aids employ mechanical guiding devices or targets to provide feedback about the user's putting stroke. However, these devices cannot be easily moved to putt from different locations during practice.
U.S. Pat. No. 5,465,972, issued to Cornett, describes a laser sighting unit which directs a laser beam to a point, such as at the hole, to aid the golfer in aligning the golf club head angle. However, the laser dot is very difficult to see, particularly in bright daylight, if the hole is more than ten feet away, and the mounting bracket requires many adjustments to properly align the beam. Moreover, this device only provides an indication of putter head alignment.
U.S. Pat. No. 5,207,429, issued to Walmsley et. al., describes a putting aid including a planar light beam source which projects a line of light on the ground. While this aid may provide an indication of putter head alignment, the light energy emitted from a laser diode in the form of a line of any practical length is of limited intensity, and is, again, often difficult to see in bright daylight.
Other putting aids, such as are disclosed in U.S. Pat. Nos. 5,611,739, issued to Carney, and 5,193,812, issued to Hendricksen, include means for projecting a light beam or dot to a target or along the ground as p art of a structure that is integral with or permanently mounted directly on the club head. These devices have the same limitations as the two above-mentioned devices. Also, they often affect the putting stroke itself, due to the location (close to the putter club head) and weight of the devices.